This isnt a thread asking for a reg. code but...

I got the reg. code for CEP...but when i DL it , there is nowhere to put it...it just has "buy online" and buy by mail...it dont ask for a usser name and password...where can I DL a CEP that will let me put in the Username and Password I have...(i've downloaded from Download.com so dont say that)...I need a download that is fo show gonna let me put in the reg. code.